I have two Advance Design trucks and both had one of those $10 Chinese hydraulic bottle jacks under the seat. I've also worked on several more trucks who's jacks were "converted" to hydraulic also.
Seems like the original screw jacks simply weren't up to the task after they were thrown back under the seat still wet and muddy from that tire change in the rain. After all, trying to get that spare out from under the bed on a cold rainy night would try an ones patients.
Denny Graham
Sandwich, IL
